Transformer



July 24, 1956 c. M- CEDERSTROM ETAL 2,755,397

TRANSFORMER Filed July 25, 1952 Inventor's: CuTtiSs M. Cederstr-om,

Llo d 5. Blair, John ORuss,

' 13 WM H Their Attorneg.

United States Patent Ofilice 2,755,397 Patented July 24, 1956TRANSFQRNIER Curtiss M. Cederstrom, Pittsiield, Lloyd 5. Blair,Williarnstown, and John C. Russ, Pittsfield, Mass., assignors to GeneralElectric Company, a corporation of New York Application July 25, 1952,Serial No. 300,904

4 Claims. (Cl. 336-60) This invention relates to transformers and moreparticularly to means for spacing continuous disk-type coils intransformers of the dry type.

In the conventional dry-type transformer construction, a laminated ironcore is provided with two or more vertically arranged leg portions andtwo or more windings are conventionally arranged concentrically aroundeach core leg. Considering only one core leg, it has been the practiceto mount a sleeve or cylinder of insulating material on the leg with alow voltage winding being wound thereon. This assembly is in turnsurrounded by another cylinder of insulating material on which is wounda high voltage winding. The high voltage winding has conventionally beenformed of a plurality of axially spaced apart horizontally arrangeddisk-shaped annular coils. In order to maintain an air duct between theunderside of each coil and the outer cylinder, these continuous diskcoils have been wound on axial spacing strips. These strips, in order tomeet thermal and electrical requirements, were made from expensiveinsulating materials. Dry-type transformers are now being constructedwith the disktype coils of the high voltage windings split into radiallyspaced apart inner and outer sections thereby providing an additionalventilating duct. It is therefore desirable to provide improved meansfor axially spacing the disk-type coils and for radially spacing theinner coil sections from the cylinder and the outer coil sections fromthe inner coil sections, such means eliminating the use of axial spacingstrips.

An object of this invention is therefore to provide an improvedtransformer of the dry type having disk-type coils incorporatingimproved means for axially and radially spacing said coils.

Further objects and adavntages of this invention will become apparent byreference to the following description and the accompanying drawing, andthe features of novelty which characterize this invention will bepointed out with particularity in the claims annexed to and forming apart of this specification.

In accordance with this invention, there is provided a dry-typetransformer having a cylindrical mounting member with a pluraltiy ofaxially-spaced apart disk-type annular coils wound thereon. Each ofthese disk-type coils has an inner section radially spaced from themounting member thereby defining a first ventilating duct and an outersection radially spaced from the inner section thereby defining a secondventilating duct. A plurality of outwardly extending spacing members arerespectively arranged between the disk coils extending from thecylindrical member outwardly beyond the outer peripheries of the diskcoils. These spacing members serve to axially space the disk coils. Inorder to provide the radial spacing, a plurality of inner spacingmembers are arranged between the inner coil sections and the cylindricalmember and another plurality of outer spacing members are respectivelyarranged between the inner and outer coil sections, these inner andouter spacing members being respectively arranged between the outwardlyextending spacing members. In order to lock these inner and outerspacing members in position, each outwardly extending spacing member hasan opening formed therethrough intermediate the inner and outer coilsections and another opening formed therethrough intermediate the innercoil sections and the cylindrical member. Each of the inner and outerspacing members has a projection formed thereon, these pro ectionsextending respectively into the openings in the outwardly extendingspacing members. The inner and outer spacing members may be axiallythinner than the axial width of the disk coils so that axial clampingpressure applied on the disk coils will not be taken by the inner andouter spacing members. In addition, in order to accommodate variationsin the radial build of the inner coil sections, the outer openings inthe outwardly extending spacing members may be elongated. Furthermore,the inner and outer spacing members may be arranged with the projectionson the inner spacing members extending in one direction and theprojections on the outer spacing members extending in the otherdirection to provide an interlocking construction.

In the drawing, Fig. l is a fragmentary side elevational view, partly insection, illustrating the improved transformer construction of thisinvention;

Fig. 2 is a fragmentary cross-sectional view taken along the line 22 ofFig. 1; and

Fig. 3 is a fragmentary exploded view showing the arrangement of theimproved spacing members of this invention.

Referring now to the drawing, there is shown a portion of a verticallyarranged leg 1 of a transformer core formed or a plurality of relativelythin laminations of magnetic material 2. The leg 1 is surrounded by aninner cylinder 3 formed of suitable insulating material which in turn isembraced by a layer-wound low voltage winding 4 wound on axial spacingmembers 6 formed of insulating material. An outer cylinder 7, alsoformed of insulating material, is arranged over the low voltage windings4 and spaced therefrom by means of outer axial spacing members 8. Highvoltage winding 9 is wound over the outer cylinder 7 and comprises aplurality of horizontal, axially spaced apart disk-type coils 10.

In order to improve the thermal efficiency of the high voltage winding,the high voltage coils 10 are each divided into an inner section 11 andan outer section 12, the inner section 11 being radially spaced from thecylinder 7 thus defining an annular ventilating duct 13 and the outersection 12 is radially spaced from the inner section 11 thus defininganother annular ventilating duct 14. The inner section 11 is formed of acontinuous radially coiled conductor 15' and the outer section 12 issimilarly formed of a continuous radially coiled conductor 16. Acrossover 17 connects the outer end of conductor 15 of coil section 11to the inner end of conductor 16 of outer coil section 12. Anothercross-over 18 connects the outer end of conductor 16 of outer coilsection 12 to the inner end of conductor 15 of inner section 11 of anadjacent coil. It is thus seen that the outer and inner sections of eachcoil are serially connected while each coil is in turn seriallyconnected to form the high voltage winding of the transformer. Thisconstruction is more fully described in copending application, SerialNo. 300,944, filed July 25, 1952, of G. Camilli and G. H. Halsey,assigned to the assignee of the present application.

In order to provide for the necessary axial and radial spacing of thecoil sections 11 and 12, a plurality of outwardly extending spacirvmembers 19, formed of suitable insulating material, such as porcelain,are respectively arranged between the disk-type coils 10. These spacingmembers extend from the outer cylinder 7 radially outward to beyond theouter periphery of the outer coil sections 12. To provide the radialspacing, a plurality of inner spacing members 20 and outer spacingmembers 21 are provided, also formed of insulating material, such asporcelain. The inner spacing members 20 are arranged between the outercylinder 7 and the inner coil section while the outer spacing members 21are arranged between the inner coil section 11 and the outer coilsections 12. The inner and outer spacing members and 21 are alsoarranged between adjacent outwardly extending spacing members 19.

In order to lock these inner and outer spacing members in position, eachof the spacing members 19 has an elongated opening 22 formedtherethrough intermediate the inner coil sections 11 and outer coilsections 12 and another opening 23 formed therethrough intermediate theinner coil sections 11 and the outer cylinder 7. The outer spacingmembers 21 are in turn provided with a pin 24 which extends into theopenings 22 in the spacing members 19 on one side of the outer spacingmembers 21. The inner spacing members 20 are provided with a similar pinwhich extends into the openings 23 in the spacing members 19 on theother side, i. e. the pins 24 of outer spacing members 21 extend in onedirection while the pins 25 of inner spacing members 20 extend in theopposite direction thus providing an interlocking construction. Theopenings 22 in the spacing members 19 are elongated so that thevariations in the radial thickness of the inner cross sections 11 can beaccommodated. In addition, the inner and outer spacing members 20 and 21are slightly thinner than the insulated width of the conductors 15 and16 of inner and outer coil sections 11 and 12, however, the totalthickness of the pins is greater than the insulated width of theconductors. Thus, the inner and outer insulators 2t and 21 cannot fallout of the winding once they are in place, however, axial clampingpressure when applied to the completed windings will not be carried bythe inner and outer spacers 20 and 21, but rather by the outwardlyextending spacing members 19 and by the conductors.

It will be readily seen that while the pins 24 and 25 of inner and outerspacing members Ztl and 21 are shown as extending in oppositedirections, the inner and outer spacing members may actually beassembled with the pins extending in the same direction withoutdeparting from the spirit of this invention. It will also be seen thatthe outwardly extending spacing members 19 can be pulled out of thewinding and easily replaced in the event of accidental chipping orcracking during manufacture. The interlocking pins 24 and 25 of innerand outer spacing members 20 and 21 are broken off during this removaloperation, however, this causes no difliculty since the remaining innerand outer spacing members are still interlocked to each other.Inspection of Fig. 2 of the drawing will show that the inner and outerducts 13 and 14 are completely unobstructed circumferentially betweenthe spacing members. With the axial spacing strips formerly used, atleast 20% of the inner duct was obstructed. It will be readily apparentthat the inner locking spacers of this invention provide an inexpensiveand practical method for axially and radially spacing the disk-typewindings of a dry transformer and further permit the splitting of eachcoil into inner and outer radially spaced apart sections to establish anadditional ventilating duct.

While we have shown and described a particular embodiment of thisinvention, further modifications and improvements will occur to thoseskilled in the art. We desire it to be understood, therefore, that thisinvention is not limited to the form shown and we intend in the appendedclaims to cover all modifications which do not depart from the spiritand scope of this invention.

What we claim as new and desire to secure by Letters Patent of theUnited States is:

1. In a transformer, a cylindrical mounting member, a plurality ofaxially-spaced apart disk-type annular coils wound on said mountingmember each having an inner section radially spaced from said mountingmember thereby defining a first annular ventilating duct and an outersection radially spaced from said inner section thereby defining asecond annular ventilating duct, a plurality of outwardly extendingspacing members respectively arranged between said disk coils andextending from said cylindrical member outwardly beyond the outerperipheries of said disk coils for axially spacing the same, saidoutwardly extending spacing members being spaced apart between each pairof adjacent said disk coils and axially aligned with respectiveoutwardly extending spacing members between adjacent pairs of said diskcoils, a plurality of inner spacing members respectively arrangedbetween said inner coil sections and said cylindrical member forproviding said first ventilating duct, and a plurality of outer spacingmembers respectively arranged between said inner and outer coil sectionsfor providing said second ventilating duct, said inner and outer spacingmembers being respectively arranged between said outwardly extendingspacing members and axially aligned therewith, each of said outwardlyextending spacing members having an outer elongated opening formedtherethrough intermediate said inner and outer coil sections and aninner opening formed therethrough intermediate said inner coil sectionsand said. cylindrical member, each of said inner spacing members havinga projection formed thereon extending into said inner opening in theoutwardly extending spacing member on one side thereof for locking saidinner spacing members in position, each of said outer spacing membershaving a projection formed thereon extending into said outer opening inthe outwardly extending spacing member on the other side thereof forlocking said outer spacing members in position, said inner and outerspacing members being axially thinner than the axial width of said diskcoils whereby said inner and outer spacing members do not carry axialclamping pressure applied to said disk coils.

2. In a transformer, a cylindrical mounting member, a plurality ofaxially-spaced apart disk-type annular coils wound on said mountingmember each having an inner section radially spaced from said mountingmember thereby'defining a first annular ventilating duct and an outersection radially spaced from said inner section thereby defining asecond annular ventilating duct, a plurality of outwardly extendingspacing members respectively arranged between said disk coils foraxially spacing the same, said outwardly extending spacing members beingspaced apart between each pair of adjacent said disk coils and axiallyaligned with respective outwardly extending spacing members betweenadjacent pairs of said disk coils, a plurality of inner spacing membersrespectively arranged between said inner coil sections and saidcylindrical member for providing said first ventilating duct, and aplurality of outer spacing members respectively arranged between saidinner and outer coil sections for providing said second ventilatingduct, said inner and outer spacing members being respectively arrangedbe tween said outwardly extending spacing members and axially alignedtherewith, each of said outwardly extending spacing members having anouter elongated opening formed therethrough intermediate said inner andouter coil sections and an inner opening formed therethroughintermediate said inner coil sections and said cylindrical member, eachof said inner spacing members having a projection formed thereonextending into said inner opening in the outwardly extending member onone side thereof for locking said inner spacing members in position,each of said outer spacing members having a projection formed thereonextending into said outer opening in the outwardly extending spacingmember on the other side thereof for locking said outer spacing membersin position.

3. In a transformer, a cylindrical mounting member, a plurality ofaxially-spaced apart disk-type annular coils wound on said mountingmember each having an inner section radially spaced from said mountingmember thereby defining a first annular ventilating duct and an outersection radially spaced from said inner section thereby defining asecond annular ventilating duct, a plurality of outwardly extendingspacing members respectively arranged between said disk coils foraxially spacing the same, said outwardly extending spacing members beingspaced apart between each pair of adjacent said disk coils and axiallyaligned with respective outwardly extending spacing members betweenadjacent pairs of said disk coils, a plurality of inner spacing membersrespectively arranged between said inner coil sections and saidcylindrical member for providing said first ventilating duct, and aplurality of outer spacing members respectively arranged between saidinner and outer coil sections for providing said second ventilatingduct, said inner and outer spacing members being respectively arrangedbetween said outwardly extending spacing members and axially alignedtherewith, each of said outwardly extending spacing members having anouter opening formed therethrough intermediate said inner and outer coilsections and an inner opening formed therethrough intermediate saidinner coil sections and said cylindrical member, each of said innerspacing members having a projection formed thereon extending into saidinner opening in the outwardly extending member on one side thereof forlocking said inner spacing members in position, each of said outerspacing members having a projection formed thereon extending into saidouter opening in the outwardly extending spacing member on the otherside thereof for locking said outer spacing members in position.

4. In a transformer, a cylindrical mounting member, a plurality ofaxially-spaced apart disk-type annular coils wound on said mountingmember each having an inner section radially spaced from said mountingmember thereby defining a first annular ventilating duct and an outersection radially spaced from said inner section thereby defining asecond annular ventilating duct, a plurality of outwardly extendingspacing members respectively arranged between said disk coils andextending from said cylindrical member outwardly beyond the outerperipheries of said disk coils for axially spacing the same, saidoutwardly extending spacing members being spaced apart between each pairof adjacent said disk coils and axially aligned with respectiveoutwardly extending spacing members between adjacent pairs of said diskcoils, a plurality of inner spacing members respectively arrangedbetween said inner coil sections and said cylindrical member forproviding said first ventilating duct, and a plurality of outer spacingmembers respectively arranged between said inner and outer coil sectionsfor providing said second ventilating duct, said inner and outer spacingmembers being respectively arranged between said outwardly extendingspacing members and axially aligned therewith, each of said outwardlyextending spacing members having an outer opening formed therethroughintermediate said inner and outer coil sections and an inner openingformed therethrough intermediate said inner coil section and saidcylindrical member, each of said inner and outer spacing members havinga projection formed thereon respectively extending into said inner andouter openings in said outwardly extending spacing members thereby tolock said inner and outer spacing members in position, the projectionsof said inner spacing members extending axially in one direction and theprojections of said outer spacing members extending axially in the otherdirection into the openings of said outwardly extending spacing membersin each axially aligned group of said outwardly extending spacingmembers.

References Cited in the file of this patent UNITED STATES PATENTS1,159,770 Hyde Nov. 9, 1915 1,747,953 Roothan Feb. 18, 1930 2,422,037Paluev June 10, 1947 2,702,374 Whitman Feb. 15, 1955

